title: Discovery of a glycerol 3-phosphate phosphatase reveals glycerophospholipid polar head recycling in Mycobacterium tuberculosis.
abstract: Functional assignment of enzymes encoded by the Mycobacterium tuberculosis genome is largely incomplete despite recent advances in genomics and bioinformatics. Here, we applied an activity-based metabolomic profiling method to assign function to a unique phosphatase, Rv1692. In contrast to its annotation as a nucleotide phosphatase, metabolomic profiling and kinetic characterization indicate that Rv1692 is a D,L-glycerol 3-phosphate phosphatase. Crystal structures of Rv1692 reveal a unique architecture, a fusion of a predicted haloacid dehalogenase fold with a previously unidentified GCN5-related N-acetyltransferase region. Although not directly involved in acetyl transfer, or regulation of enzymatic activity in vitro, this GCN5-related N-acetyltransferase region is critical for the solubility of the phosphatase. Structural and biochemical analysis shows that the active site features are adapted for recognition of small polyol phosphates, and not nucleotide substrates. Functional assignment and metabolomic studies of M. tuberculosis lacking rv1692 demonstrate that Rv1692 is the final enzyme involved in glycerophospholipid recycling/catabolism, a pathway not previously described in M. tuberculosis.
authors.affiliation: Division of Mycobacterial Research, Medical Research Council National Institute for Medical Research, London NW7 1AA, United Kingdom.
authors.forename: Gérald
authors.initials: G
authors.lastname: Larrouy-Maumus
authors.forename: Tapan
authors.initials: T
authors.lastname: Biswas
authors.forename: Debbie M
authors.initials: DM
authors.lastname: Hunt
authors.forename: Geoff
authors.initials: G
authors.lastname: Kelly
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Tsodikov
authors.forename: Luiz Pedro Sório
authors.initials: LP
authors.lastname: de Carvalho
mesh_terms: D020134:Catalytic Domain; D020404:Glycerophospholipids / Q000378:metabolism*; D008958:Models, Molecular; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D010744:Phosphoric Monoester Hydrolases / Q000737:chemistry / Q000378:metabolism*; D012995:Solubility
chemical_list: D020404:Glycerophospholipids; C583817:glycerol 3-phosphate phosphatase, Mycobacterium tuberculosis; D010744:Phosphoric Monoester Hydrolases
keywords: enzyme function; haloacid dehalogenase superfamily; pathway discovery